In general, as to an active matrix liquid crystal display device fitted with TFT, a pixel electrode and the TFT to control voltage applied to the pixel electrode possess matrix-aligned active matrix substrates, liquid crystals are sandwiched between this active matrix substrate and a facing substrate, and the liquid crystals are driven by voltage applied between the pixel electrode and another electrode. In this case, there is a twisted nematic liquid crystal and vertical alignment system liquid crystal display device in which the pixel electrode of the active matrix substrate is a transparent electrode, and voltage is applied between it and a transparent common electrode formed on the facing substrate as another electrode to drive liquid crystals, or an in-plane switching system liquid crystal display device in which employing a pixel electrode of an active matrix substrate and a counterpart pectinate electrode to the common electrode, voltage is applied between these electrodes to drive liquid crystals. At any rate, the foregoing TFT and pixel electrode are desired to be formed on the active matrix substrate, and at present, these TFT and pixel electrode are formed by a photolithography technique.
A liquid crystal display device called the in-plane switching system liquid crystal display device is generally compared with a liquid crystal display device called a twisted nematic liquid crystal and vertical alignment system liquid crystal display device, and is one in which a display electrode and a reference electrode are provided on the surface of the region corresponding to a unit pixel on the liquid crystal layer side of one transparent substrate or both transparent substrates among the transparent substrates provided facing to each other via the liquid crystal layer, and light transmitting the foregoing liquid crystal layer is modulated by electric field generated parallel to the transparent substrate between this display electrode and the reference electrode.
On the other hand, the twisted nematic liquid crystal and vertical alignment system liquid crystal display device possesses a pixel electrode composed of a transparent electrode and a common electrode provided facing on the surface of each region corresponding to a unit pixel on the liquid crystal layer side of the transparent substrate provided facing to each other via the liquid crystal layer, and is one in which light transmitting the foregoing liquid crystal layer is modulated by electric field generated perpendicularly to the transparent substrate between this pixel electrode and the common electrode. The in-plane switching system liquid crystal display device differing from such the twisted nematic liquid crystal and vertical alignment system liquid crystal display device, by which clear images can be confirmed even though observing from a viewing field at a large angle with respect to the display surface, is known as one exhibiting so-called excellent viewing field at an angle. In addition, liquid crystal displays composed of such the structure are disclosed in detail, for example, in Japanese Patent O.P.I. Publication No. 5-505247, Japanese Patent Examined Publication No. 63-21907, and Japanese Patent O.P.I. Publication No. 6-160878.
Such the in-plane switching system liquid crystal display device produces a problem such that a display trouble which has not been so far experienced in the twisted nematic liquid crystal and vertical alignment system liquid crystal display device is generated when high voltage such as static charge or the like is applied from outside the surface of the liquid crystal display panel. That is, the in-plane switching system liquid crystal display device has a structure having no conductive layer in which a shielding function against static charge or the like from outside is provided between the display electrode and the reference electrode placed parallel or nearly parallel to the liquid crystal. Supposedly, when such the conductive layer is provided, electric field from the display electrode is terminated not on the reference electrode side but on the conductive layer side, whereby displaying can not be appropriately carried out with the electric field.
Electric field corresponding to a picture signal generated parallel to the transparent substrate between the display electrode and the reference electrode because of no possession of a shielding function is influenced by static charge or the like from outside. The liquid crystal display panel itself is charged by static charge or the like from the outside, and this electrification generates electric field perpendicularly to the transparent substrate.
In order to solve the above-described problem, concerning the case where high voltage such as static charge or the like is applied from outside the surface of a liquid crystal display device, disclosed is the liquid crystal display device exhibiting reduced generation of the display trouble (refer to Patent Document 1, for example).
However, as the in-plane switching system liquid crystal display device or the twisted nematic liquid crystal and vertical alignment system liquid crystal display device, it was found out that in cases where a conductive layer was formed by a sputtering method, short-circuiting was easy to be generated in an electrode section, and the transparent substrate was damaged, resulting in occurrence of the broken transparent substrate. Further, since bubbles are generated in a liquid crystal layer when the conductive layer is formed by a sputtering method after filling liquid crystals in the liquid crystal layer, what is happening now is that a high-definition liquid crystal display device can not be obtained.
Further, known is a method of forming a conductive layer via coating of a coating solution containing conductive particles, but since a sintering treatment has to be carried out at a high temperature after drying a conductive film formed via a coating process in this method, a great deal of time is desired to be consumed to form the conductive film, and there is produced a problem such as lowering of optical transparency of a formed conductive film and weak adhesion to a substrate.
Patent Document 1: Japanese Patent No. 2758864